Just an update on this topic as it had lots of input and ideas.
I'm running ZoL (ubuntu) on 2 boxes Dell R510 with a H200 flashed to IT mode, 12x 600GB 15K and 1TB Samsung 850 PRO for L2ARC and chinese intel X540-T1 for the 10gb network. So far working very well. I'm running about 10 RDS servers, 3 exchange, a few file servers and other random VMs, about 30 VMs in total. So far so good, excellent performance considering the low investment. I'm replicating the VMs using Veeam to the second box for the time being, but at a later stage I should connect the boxes using 40GB infiniband using RDMA for a high availability scenario, but it seems I need a hardwrae raid controller and have all disks presented as individual RAId-0, so I'm not sure yet about this.
I'm running ZoL (ubuntu) on 2 boxes Dell R510 with a H200 flashed to IT mode, 12x 600GB 15K and 1TB Samsung 850 PRO for L2ARC and chinese intel X540-T1 for the 10gb network. So far working very well. I'm running about 10 RDS servers, 3 exchange, a few file servers and other random VMs, about 30 VMs in total. So far so good, excellent performance considering the low investment. I'm replicating the VMs using Veeam to the second box for the time being, but at a later stage I should connect the boxes using 40GB infiniband using RDMA for a high availability scenario, but it seems I need a hardwrae raid controller and have all disks presented as individual RAId-0, so I'm not sure yet about this.